Notices will be sent out to developers of up to 100 mobile apps that are not compliant with California privacy law, starting with those who have the most popular apps available on mobile platforms, the office of the state's attorney general Kamala D. Harris said Tuesday.

The developers are required to post conspicuously within 30 days a privacy policy within their app that informs users of what personally identifiable information about them is being collected and what will be done with that private information, the office said in a statement.

The letters to the developers invoke the California Online Privacy Protection Act, which requires that an operator of a commercial website or online service that collects personally identifiable information through the Internet about individual consumers residing in California who use or visit their sites or online services must post a privacy policy that complies with specified requirements.

An operator of a mobile app that uses the Internet to collect personally identifiable information is an online service within the meaning of the Act, according to a sample copy of the letter.

Failure to comply can lead to a fine of up to US$2,500 each time a non-compliant app is downloaded.

Harris arrived at an agreement in February committing leading operators of mobile application platforms to improve privacy protections on apps. Amazon, Apple, Google, Hewlett-Packard, Microsoft and Research In Motion agreed to ensure that mobile apps comply with the California Online Privacy Protection Act, including by providing a mechanism for users to report apps that are not in compliance with applicable terms of service and the laws.

The agreement would also allow consumers the opportunity to review an app's privacy policy before they download the app rather than after, and will offer consumers a consistent location for an app's privacy policy on the application-download screen, the attorney general's office said in February.

The addition of Facebook in June to the list of companies to sign the agreement, extended privacy protections to include social apps in Facebook's App Center.

The state has taken a tough stand on online privacy, setting up a Privacy Enforcement and Protection Unit within the state's justice department earlier this year. The California Online Privacy Protection Act is one of the privacy laws that the unit is charged with enforcing.

John Ribeiro covers outsourcing and general technology breaking news from India for The IDG News Service. Follow John on Twitter at @Johnribeiro. John's e-mail address is john_ribeiro@idg.com